The present invention relates to the extraction of non-polar isothiocyanates from plants and stable compositions of the same for use as dietary supplements.
Finding effective methods for preventing cancer has been a major research goal of the past century. A great deal of research has been done on the impact diet has on a person""s risk of cancer. Numerous studies show that eating vegetables, especially vegetables belonging to the family Brassicaceae, such as brassica vegetables, may reduce the risk of developing cancer of various organs. See, for example, U.S. Pat. No. Re. 36,784, which is hereby incorporated by reference.
These brassica vegetables are believed to reduce the risk of cancer because they contain glucosinolates that are converted into isothiocyanates by contact with endogenous myrosinase enzymes when the cells of the vegetables are disrupted. Some isothiocyanates are potent phase II enzyme inducers, which can protect cells against the toxic and neoplastic effects of carcinogens. Therefore, a number of isothiocyanates from the brassica vegetables are biologically useful in preventing cancer.
The brassica vegetables may contain glucosinolates that are converted to isothiocyanates that are characterized as being either polar or non-polar. Certain non-polar isothiocyanates are desirable because of their implication in the prevention of certain cancers, most notably lung cancer. Benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC) are particularly useful in the prevention of lung cancer.
Although it is desirable to include non-polar isothiocyanates in dietary supplements, it is difficult to do so using the present methods. Extraction of isothiocyanates from vegetables tends to be carried out using an aqueous solvent, which is more effective for extracting polar isothiocyanates than non-polar isothiocyanates. Furthermore, some of the biologically important non-polar isothiocyanates tend to be volatile and unstable once extracted. Thus, a stable composition suitable for use in dietary supplements is not available according to currently used procedures.
A method for extracting non-polar isothiocyanates from plant materials, especially those that are important to health and disease prevention, is needed. There is also a need to provide stable compositions containing non-polar isothiocyanates that can be conveniently delivered to consumers wanting them.
The methods of the present invention solve the problems associated with prior art extraction methods to produce compositions of non-polar isothiocyanates. These compositions stabilize the isothiocyanates and are useful for dietary supplements.
In one aspect of the invention, a method of extracting a non-polar isothiocyanate from a plant includes providing fresh or dehydrated plant material having at least one glucosinolate that will form a corresponding non-polar isothiocyanate and having at least one endogenous myrosinase enzyme. Thereafter, water is added to the plant material and the mixture is homogenized, to allow for conversion of the glucosinolate(s) to isothiocyanate(s). A vegetable oil is then added to the water and plant material homogenate and the resulting mixture is blended. Finally, the oil phase is separated from the aqueous phase and solids such that the non-polar isothiocyanates partition into the oil phase.
In another aspect of the invention, a stable composition comprises a non-polar isothiocyanate and a vegetable oil.
In still another aspect of the invention, a method of preventing cancer comprises administering the stable composition.
In still another aspect of the invention, a dietary supplement comprises a non-polar isothiocyanate present in a therapeutically effective amount to help with cancer prevention, a vegetable oil-based carrier and from about 0.1% to about 0.5% of mixed tocopherols or one of its individual constituents, such as alpha-tocopherol.
The above and other aspects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments. It is noted that, unless otherwise stated, all percentages given in this specification and the appended claims refer to percentages by weight.